The path to N3LO parton distributions

Abstract
We extend the existing leading (LO), next-to-leading (NLO), and next-to-next-to-leading order (NNLO) NNPDF4.0 sets of parton distribution functions (PDFs) to approximate next-to-next-to-next-to-leading order (aN3LO). We construct an approximation to the N3LO splitting functions that includes all available partial information from both fixed-order computations and from small and large x resummation, and estimate the uncertainty on this approximation by varying the set of basis functions used to construct the approximation. We include known N3LO corrections to deep-inelastic scattering structure functions and extend the FONLL general-mass scheme to 𝑂(𝛼𝑠3) accuracy. We determine a set of aN3LO PDFs by accounting both for the uncertainty on splitting functions due to the incomplete knowledge of N3LO terms, and to the uncertainty related to missing higher corrections (MHOU), estimated by scale variation, through a theory covariance matrix formalism. We assess the perturbative stability of the resulting PDFs, we study the impact of MHOUs on them, and we compare our results to the aN3LO PDFs from the MSHT group. We examine the phenomenological impact of aN3LO corrections on parton luminosities at the LHC, and give a first assessment of the impact of aN3LO PDFs on the Higgs and Drell–Yan total production cross-sections. We find that the aN3LO NNPDF4.0 PDFs are consistent within uncertainties with their NNLO counterparts, that they improve the description of the global dataset and the perturbative convergence of Higgs and Drell–Yan cross-sections, and that MHOUs on PDFs decrease substantially with the increase of perturbative order.
Main Authors
Format
Articles Research article
Published
2024
Series
Publication in research information system
Publisher
Springer
The permanent address of the publication
https://urn.fi/URN:NBN:fi:jyu-202407085147Use this for linking
Review status
Peer reviewed
ISSN
1434-6044
DOI
https://doi.org/10.1140/epjc/s10052-024-12891-7
Language
English
Published in
European Physical Journal C
Citation
  • Ball, R. D., Barontini, A., Candido, A., Carrazza, S., Cruz-Martinez, J., Del Debbio, L., Forte, S., Giani, T., Hekhorn, F., Kassabov, Z., Laurenti, N., Magni, G., Nocera, E. R., Rabemananjara, T. R., Rojo, J., Schwan, C., Stegeman, R., & Ubiali, M. (2024). The path to N3LO parton distributions. European Physical Journal C, 84, Article 659. https://doi.org/10.1140/epjc/s10052-024-12891-7
License
CC BY 4.0Open Access
Funder(s)
Research Council of Finland
Research Council of Finland
Funding program(s)
Centre of Excellence, AoF
Academy Research Fellow, AoF
Huippuyksikkörahoitus, SA
Akatemiatutkija, SA
Research Council of Finland
Additional information about funding
R.D.B, L.D.D, and R.S. are supported by the U.K. Science and Technology Facility Council (STFC) consolidated grants ST/T000600/1 and ST/X000494/1. F.H. is supported by the Academy of Finland project 358090 and is funded as a part of the Center of Excellence in Quark Matter of the Academy of Finland, project 346326. E.R.N. is supported by the Italian Ministry of University and Research (MUR) through the “Rita Levi-Montalcini” Program. M.U. and Z.K. are supported by the European Research Council under the European Union’s Horizon 2020 research and innovation Programme (grant agreement n.950246), and partially by the STFC consolidated grant ST/T000694/1 and ST/X000664/1. J.R. is partially supported by NWO, the Dutch Research Council. C.S. is supported by the German Research Foundation (DFG) under reference number DE 623/6-2.
Copyright© The Author(s) 2024

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